Metallocene complexes

ABSTRACT

In metallocene complexes of a metal of transition group IV, V or VI of the Periodic Table, at least one substituted or unsubstituted cyclopentadienyl radical is bound to an element of group III of the Periodic Table which is in turn a constituent of a bridge between this cyclopentadienyl radical and the metal atom and bears an organonitrogen, organophosphorus or organosulfur group as sole further substituent.

The present invention relates to metallocene complexes of metals oftransition group IV, V or VI of the Periodic Table, in which at leastone substituted or unsubstituted cyclopentadienyl radical is bound to anelement of group III of the Periodic Table which is in turn aconstituent of a bridge between this cyclopentadienyl radical and themetal atom and bears an organonitrogen, organophosphorus or organosulfurgroup as sole further substituent.

Metallocene catalysts are gaining increasing importance in thepolymerization of α-olefins. Metallocene catalysts are particularlyadvantageous for the copolymerization of ethylene with higher α-olefinssince they result in particularly uniform incorporation of comonomerinto the copolymer. Among metallocene catalysts, bridged metallocenecomplexes have attracted particular interest since they generally give ahigher productivity than do the unbridged complexes, result inparticularly good incorporation of comonomer and are also, for example,suitable for preparing highly isotactic polypropylene.

Bridge metallocene complexes in which the cyclopentadienyl radicals arejoined by SiMe₂ or C₂H₄ bridges have been known for a long time. Suchmetallocene compounds are described, for example, in EP-A-336 128.

Apart from metallocene complexes in which the cyclopentadienyl radicalsare bridged via silicon or carbon atoms, bridged metallocenes in whichone or more boron atoms perform the bridging function are also known.Thus, for example, boron-bridged metallocene complexes in which theboron atom bears an alkyl or aryl substituent are known (J. Organomet.Chem., 1997, 536-537, 361). However, the preparation of thesemetallocene complexes is very complicated; nothing is known aboutpolymerizations using these complexes.

DE-19 539 650 likewise describes bridged metallocene complexes in whichboron, inter alia, may be present as bridge member. The boron atomshaving a bridging function may be substituted by various radicals suchas alkyl, aryl, benzyl and halogens and also by alkoxy or hydroxygroups. Once again, nothing is known about the polymerization behaviorof such metallocene complexes.

Organometallics, 1997, 16, 4546, describes boron-bridged metallocenes inwhich the bridging boron atom is substituted by a vinyl group and isadditionally coordinated by a Lewis base. However, the yields in thesynthesis of these complexes are very poor and the polymerization ofethylene proceeds unsatisfactorily and leads only to low molecularweight polymer.

EP-A-0 628 566 describes bridged metallocene complexes whose genericformula nominates carbon, silicon, tin, germanium, aluminum, nitrogen,phosphorus and also boron as bridging atoms and in which the bridgingatoms may be substituted by many substituents among which thedialkylamino group is mentioned. However, metallocene complexes havingan amino-substituted boron bridge are not explicitly mentioned at anypoint, nor are properties of such complexes described.

The boron-bridged metallocene complexes known from the prior art aremostly difficult to prepare and do not offer, of offer only to a veryrestricted extent, the opportunity of influencing the electronicconditions in the cyclopentadienyl groups by means of electron-donatingsubstituents on the boron atom and thus making it possible to influencethe catalytic activity of the complexes.

It is an object of the present invention to provide metallocenecomplexes which no longer have the disadvantages described, are simpleto prepare and, in particular, offer the opportunity of influencing theelectronic conditions on the cyclopentadienyl radicals.

We have found that this object is achieved by the metallocene complexesmentioned at the outset. Furthermore, we have found a process forpreparing such metallocene complexes and the use of the metallocenecomplexes as catalyst components for the homopolymerization andcopolymerization of C₂-C₁₀-α-olefins.

As element of group III of the Periodic Table, particular mentioned maybe made of boron and aluminum, with boron being particularly preferred.

Among the substituents which can act as the sole further substituentwhich occupies the third valence of the element of group III of thePeriodic Table in addition to the bonds to a cyclopentadienyl radicaland the other constituents of the bridge, particular mention may be madeof organonitrogen, organophosphorus or organosulfur groups which, inaddition to these heteroatoms, comprise up to 20 carbon atoms and up to4 silicon atoms.

The metallocene complexes of the present invention may contain 1 or 2cyclopentadienyl radicals. Preference is given to metallocene complexesof the formula I

where the variables have the following meanings:

M is a metal atom of transition group IV, V or VI of the Periodic Table,

D is an element of group III of the Periodic Table,

R¹,R²,R³,R⁴ are each hydrogen, C₁- to C₁₀-alkyl, 5-7-membered cycloalkylwhich may in turn bear a C₁-C₁₀-alkyl group as substituent, C₆- toC₁₅-aryl or arylalkyl, where two adjacent radicals R¹ to R⁴ may alsoform 5-7-membered cyclic groups which may in turn bear C₁-C₁₀-alkylgroups or SiR⁶ ₃ groups as substituents or include further fused-on ringsystems,

R⁵ is hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl or -arylalkyl orC₁-C₁₀-trialkylsilyl,

R⁶ is C₁-C₄-alkyl,

m is the number of the transition group of the metal atom M minus 2,

n is 2 when X¹ is nitrogen or phosphorus and is 1 when X¹ is sulfur,

X¹ is nitrogen, phosphorus or sulfur,

X² is hydrogen, C₁-C₁₀-hydrocarbyl, N(C₁-C₁₅-hydrocarbyl)₂ or halogen,

A is a radical

 or a radical which is coordinated to M via an oxygen, sulfur, nitrogenor phosphorus atom.

Suitable metal atoms M are, in particular, the elements of transitiongroup IV of the Periodic Table, i.e. titanium, zirconium and hafnium,with titanium and zirconium being preferred and zirconium beingparticularly preferred.

The cyclopentadienyl groups in formula I may be substituted orunsubstituted. Among the substituted metallocene complexes, those whichare substituted by C₁-C₄-alkyl groups display particularly advantageousproperties. Possible alkyl substituents are, for example, methyl, ethyl,n-propyl and n-butyl. The cyclopentadienyl radicals can bemonosubstituted or polysubstituted, with monosubstituted anddisubstituted cyclopentadienyl radicals having been found to beparticularly advantageous. Preference is also given to cyclopentadienylradicals in which 2 adjacent radicals R¹ to R⁴ are joined to form 5- to7-membered cyclic groups. Examples which may be mentioned arecyclopentadienyl groups derived from indenyl, tetrahydroindenyl,benzindenyl or fluorenyl, with these ring systems in turn being able tobe substituted by C₁-C₁₀-alkyl groups or by trialkylsilyl groups.

In the metallocene complexes of the present invention having 2cyclopentadienyl units, the bridging atom of the element of group III ofthe Periodic Table is directly bound to these two cyclopentadienylunits.

Among these dicyclopentadienyl complexes, particular preference is givento metallocene complexes in which

A is a radical

In the case of monocyclopentadienyl complexes, on the other hand, theradical A is not a cyclopentadienyl radical but rather a radical whichis coordinated to M via an oxygen, sulfur, nitrogen or phosphorus atom.Possible groups A are, in particular, the following atoms or groups:—O—, —S—, —NR⁹—, —PR⁹— and uncharged 2-electron donor ligands such as—OR⁹, —SR⁹, —NR⁹ ₂ or —PR⁹ ₂. In these formulae, R⁹ is hydrogen or analkyl, aryl, silyl, halogenated alkyl or halogenated aryl group havingup to 10 carbon atoms. Particular preference is given to metallocenecomplexes in which A is a group

—ZR⁷ ₂—NR⁸—

in which

Z is silicon or carbon and

R⁷,R⁸ are hydrogen, silyl, alkyl, aryl or combinations of these radicalshaving up to 10 carbon or silicon atoms.

Examples of radicals R⁷ and R⁸ are, in particular, hydrogen,trimethylsilyl, methyl, tert-butyl and ethyl. Z is preferably a carbonatom.

In the metallocene complexes of the present invention, the bridging atomof the element of group III of the Periodic Table, which in itself hasLewis acid character, is substituted by a compound having Lewis basecharacter. Due to its electron donor function, the Lewis basesubstituent influences the electronic conditions on the cyclopentadienylradical and thus also the electronic environment of the metal atom. TheLewis base substituent can be bound to the bridging atom of the elementof group III of the Periodic Table via a nitrogen, phosphorus or sulfuratom, with substituents having a nitrogen atom being particularlypreferred. The atom X¹ can bear either hydrogen, C₁-C₁₀-alkyl groups orC₁-C₁₀-trialkylsilyl groups. Suitable alkyl groups are, in particular,C₁-C₄-alkyl groups and very particularly methyl or ethyl groups.

The central atom M is substituted not only by the ligands mentioned butalso by ligands X². Suitable ligands X² are, in particular, lower alkylgroups such as methyl and ethyl, but X² is preferably halogen,particularly preferably chlorine.

The metallocene complexes of the present invention can be prepared invarious ways. In the case of compounds having a bridging boron atom, forexample, a method which has been found to be advantageous for preparingsuch metallocene complexes is to react a compound R⁵ _(n)X¹—BY₂ (II),where Y is halogen, with a compound

where M′ is an alkali metal or alkaline earth metal, in the presence ofa metal alkyl and then to allow the reaction product to react with an Mhalide compound and finally with an oxidant.

In formula (II), Y is preferably chlorine. The preparation of compoundsof the formula (II) is described, for example, in Angew. Chem. 1964, 76,499. The synthesis of the metallocene complexes of the present inventionaccording to the above-described process is particularly simple and canbe carried out in only one reaction vessel. The metal alkyl serves asdeprotonating reagent; preference is given to using alkali metal alkylsor alkaline earth metal alkyls, in particular butyllithium. Suitable Mhalide compounds are, for example, titanium trichloride derivatives,particularly preferably titanium trichloride tris(THF) adduct. Asoxidant in the final oxidation reaction, it is possible to use, forexample, lead dichloride. After filtration of the reaction mixture, themetallocene complex can be isolated from the solution.

The metallocene complexes of the present invention can be used ascatalyst components for the homopolymerization and copolymerization ofC₂-C₁₀-α-olefins. To carry out the polymerization, it is generallynecessary to convert the metallocene complexes into a cationic complexby means of suitable compounds capable of forming metalloceniuim ions.Possible compounds capable of forming metallocenium ions are, forexample, aluminoxanes, preferably ones having a degree ofoligomerization of from 3 to 40, particularly preferably from 5 to 30.

Apart from aluminoxanes, further cation-forming compounds are, inparticular, borane and borate compounds which are a noncoordinatinganion or can be converted into such an anion and form an ion pair withthe metallocenium complex. Suitable reagents of this type for activatingthe metallocene complexes are well known to those skilled in the art andare described, for example, in EP-B1-0468537.

Particularly for polymerizations in the gas phase and in suspension, itmay be necessary to apply the metallocene complexes and possibly theactivating reagents to support materials. Such support materials andmethods of applying catalyst complexes to supports are well known tothose skilled in the art. Suitable support materials are, in particular,inorganic oxides such as silica gel, aluminum oxide or magnesium salts.

The above-described catalyst systems make it possible to preparepolyolefins, in particular polymers of 1-alkenes. For the purposes ofthe present invention, these are homopolymers and copolymers ofC₂-C₁₀-alk-1-enes, with preferred monomers being ethylene, propylene,1-butene, 1-pentene and 1-hexene. These catalyst systems areparticularly useful for polymerizing ethylene with 1-butene or 1-hexene.

As polymerization processes, it is possible to employ all knownprocesses, i.e., for example, gas-phase processes, suspension processesor polymerization processes in solution.

When used for the polymerization of ethylene and the copolymerization ofethylene with other α-olefins, the metallocene complexes of the presentinvention display good polymerization activity and lead to polymershaving a relatively high molecular weight. The following examplesillustrate the invention.

EXAMPLES

Syntheses of the ligands and complexes were carried out in the absenceof air and moisture. The following reagents were prepared by literaturemethods: (Me₃Si)₂NBCl₂ (Angew. Chem. 1964, 76, 499), Na(C₅H₅) (Chem.Ber. 1956, 89, 434), Ti(NMe₂)₄ (J. Chem. Soc., 1960, 3857),[TiCl₃(THF)₃] (Inorg. Synth. 1982, 21, 135), (C₄H₈N)₂BCl (Chem. Ber.1994, 127, 1605), (i-Pr)₂NBCl₂ (J. Chem. Soc., 1960, 5168).

NMR: Varian Unity 500 at 499.843 MHz (¹H, internal standard: TMS),150.364 MHz (¹¹B, BF₃*OEt₂ in C₆D₆ as external standard), 123.639 MHz(¹³C{¹H}, APT, internal standard: TMS); unless indicated otherwise, allNMR spectra were recorded in CD₂Cl₂ as solvent. Mass spectra wererecorded on a Finnigan MAT 95 (70 eV) and the elemental analyses (C, H,N) were obtained using a Carlo-Erba elemental analyzer, model 1106.

Example 1 Preparation of Li₂[(Me₃Si)₂NB(C₅H₄)₂] (1)

8.23 g (93.54 mmol) of Na(C₅H₅) were suspended in 100 ml of hexane. Atroom temperature, a solution of 11.13 g (46.05 mmol) of (Me₃Si)₂NBCl₂ in20 ml of hexane was added dropwise. After stirring for 2 hours, thereaction mixture was cooled to 0° C. 57.6 ml (92.10 mmol) of a 1.6 molarsolution of butyllithium in hexane were added dropwise. A whiteprecipitate was formed immediately. The reaction mixture was warmed toroom temperature and then stirred for another one hour. The volatileconstituents were then removed under reduced pressure and the solidresidue was extracted overnight using 150 ml of hexane. The mixture wasfiltered and the solid was dried under reduced pressure.

Yield: 14.13 g (98%) of white pyrophoric solid. ¹H-NMR (d₆-THF): δ=0.01(s, 18H, Si(CH₃)₃), 5.83 (m, 4H, C₅H₄), 6.45 (m, 4H, C₅H₄). ¹¹B-NMR:δ=46.6 (s); ¹³C-NMR: δ=4.31 (s, Si(CH₃)₃), 103.16, 106.63, 116.63(C₅H₄).

Example 2 Preparation of Cl₂Ti[(C₅H₄)₂BN(SiMe₃)₂] (2)

Method A:

3.20 g (13.24 mmol) of (Me₃Si)₂NBCl₂ and 2.39 g (27.17 mmol) of Na(C₅H₅)were reacted as described above. The resulting filtrate was admixed with16.6 ml of a 1.6 molar solution of butyllithium in hexane. The slightlyyellowish suspension was stirred at room temperature for 2 hours andthen cooled to −100° C. 4.90 g (13.24 mmol) of TiCl₃(THF)₃ and 20 ml ofTHF were then added. The reaction mixture was warmed to roomtemperature, whereupon the color changed from light-brown to darkviolet. The suspension was stirred for 3 hours and then treated with1.84 g (6.62 mmol) of PbCl₂. After stirring for 16 hours, the volatileconstituents were removed under reduced pressure. The solid obtained wasextracted with 50 ml of dichloromethane and then filtered off. Yield:4.43 g (80%) of dark red solid after the solution had been stored at−30° C.

¹H-NMR: δ=0.08 (s, 18H, Si(CH₃)₃), 5.53 (m, 4H, C₅H₄), 7.05 (m, 4H,C₅H₄). ¹¹B-NMR: δ=46.6 (s); ¹³C-NMR: δ=4.89 (s, Si(CH₃)₃), 114.85,133.44 (C₅H₄); MS: m/e (%): 417 (35) (M⁺), 402 (15) (M⁺-Me), 382 (25)(M⁺—Cl); C₁₆H₂₆NBCl₂Si₂Ti (418.18): calc.: C, 45.96, H, 6.27, N, 3.35;found: C, 46.56, H, 7.05, N, 2.87.

Example 3 Preparation of (Me₂N)₂Ti[(C₅H₄)₂BN(SiMe₃)₂] (3)

2.08 g (8.60 mmol) of (Me₃Si)₂NBCl₂ and 1.51 g (17.20 mmol) of Na(C₅H₅)were reacted as described above. The resulting filtrate was cooled to−30° C. and a solution of 1.93 g (8.60 mmol) of Ti(NMe₂)₄ in 5 ml ofhexane was added dropwise. The reaction mixture was slowly warmed toroom temperature, whereupon the color changed from yellow to dark red.After stirring for 1 hour, the volatile constituents were removed underreduced pressure and the resulting solid was suspended in 10 ml ofhexane. After filtration and subsequent removal of the volatileconstituents under reduced pressure, 1.05 g (28%) of (3) was obtained asa dark red solid.

¹H-NMR: δ=0.09 (s, 18H, Si(CH₃)₃), 3.14 (s, 12H, N(CH₃)₂), 5.42; (m, 4H,C₅H₄), 6.73 (m, 4H, C₅H₄). ¹¹B-NMR: δ=46.9 (s); ¹³C-NMR: δ=4.89 (s,Si(CH₃)₃), 51.11 (N(CH₃)₂ 112.73, 131.66 (C₅H₄); C₂₀H₃₈N₃BSi₂Ti(435.43): calc.: C, 55.17, H, 8.80, N, 9.65; found: C, 55.62, H, 8.22,N, 9.59.

Example 4 Peparation of (Me₂N)ClTi[(C₅H₄)₂BN(SiMe₃)₂] (4)

1.09 g (4.50 mmol) of (Me₂Si)₂NBCl₂ and 0.88 g (10.00 mmol) of Na(C₅H₅)were reacted as described above. The resulting filtrate was cooled to−30° C. and a solution of 1.01 g (4.50 mmol) of Ti(NMe₂)₄ in 5 ml ofhexane was added dropwise. The reaction mixture was slowly warmed toroom temperature. 0.84 g (4.50 mmol) of (C₄H₈N)₂BCl was added to thissolution. After stirring for 1 hour, the volatile constituents wereremoved under reduced pressure and the resulting solid was suspended in20 ml of hexane. After filtration and subsequent storage at −30° C.,0.79 g (41%) of (4) was obtained as a dark red crystalline solid.

¹H-NMR (CDCl₃): δ=0.28 (s, 18H, Si(CH₃)₃), 3.26 (s, 6H, N(CH₃)₂), 5.08(m, 2H, C₅H₄), 5.29 (m, 2H, C₅H₄), 6.62 (m, 2H, C₅H₄), 6.83 (m, 2H,C₅H₄). ¹¹B-NMR: δ=46.4 (s); ¹³C-NMR: δ=7.53 (s, Si(CH₃)₃), 57.54(N(CH₃)₂), 115.73, 117.57, 126.93, 128.54 (C₅H₄); C₁₈H₃₂N₂BClSi₂Ti(426.80): calc.: C, 50.66, H, 7.56, N, 6.56; found: C, 50.23, H, 7.59,N, 6.39.

Example 5 Preparation of Cl₂Ti[(C₅H₄)₂BN(SiMe₃)₂] (2)

Method B:

1.45 g (6.00 mmol) of (Me₃Si)₂NBCl₂ and 1.08 g (12.30 mmol) of Na(C₅H₅)were reacted as described for (4). A solution of 1.34 g (6.00 mmol) ofTi(NMe₂)₄ in 5 ml of hexane was added dropwise to the filtrate obtained.The reaction mixture was subsequently admixed with 2.24 g (12.00 mmol)of (C₄H₈N)₂BCl. This gave 0.38 g (15%) of (2) as a dark red crystallinesolid.

Example 6 Preparation of (i-Pr)₂NB(C₅—H₅)₂ (5)

A solution of 10.33 g (56.8 mmol) of (i-Pr)₂NBCl₂ in 25 ml of hexane wasadded dropwise at 20° C. to a suspension of 10.0 g (113.6 mmol) ofNa(C₅H₅) in 100 ml of hexane. After the exothermic reaction had abated,the mixture was stirred at 20° C. for 2 days. The ¹¹B-NMR spectrum ofthe reaction solution then displayed only 1 signal at about 40 ppm forthe disubstituted product (starting material: 31 ppm, mono-Cp-chloroproduct: 35 ppm). The reaction mixture was filtered to removeprecipitated NaCl.

To prepare the pure compound, the solvent was removed under reducedpressure, leaving a yellowish orange, turbid oil. The residue wassubjected to fractional distillation at 5*10⁻² mbar. At the pressureindicated, the product was obtained at 72-75° C. initially as a clear,yellowish liquid, then after 10 minutes at 20° C. in the form ofslightly yellowish, low-melting crystals (yield: 18%, thermolabilesubstance, substantial decomposition during distillation).

Analysis: ¹¹B-NMR (C₆D₆): 40.18 ppm, ¹H-NMR (C₆D₆): 1.06, 1.08, 1.14(each doublet, CH₃ on isoprop., 3 isomers!); 2.85, 2.94, 3.04 (eachmultiplet, CH₂ on the Cp ring); 3.62-3.92 (3*multiplet, CH on isoprop.);6.2-6.8 (multiplets, CH on the Cp ring). MS (EI) (fragment, %): 241 (M⁺,95%), 226 (M′-CH₃, 95%), 198 (M⁺-iprop, 30%), 176 (M⁺-Cp, 45%) (correctisotope pattern).

Example 7 Peparation of (i-Pr)₂NB(C₅H₅)₂Li₂ (6)

2 equivalents of butyllithium solution (1.6 M) were added dropwise at10° C. to the filtrate of the reaction solution from (5), and themixture was stirred overnight at 20° C., resulting in precipitation of asnow white solid. The solid was filtered off under protective gas andwashed twice with 50 ml each time of hexane. This gave the dilithio saltas a white, highly pyrophoric powder in quantitative yield.

Analysis: ¹H-NMR (d₈-THF): 1.23 ppm (doublet, CH₃); 4.52; (multiplet, CHon isoprop): 5.73 and 5.83 (each pseudo triplet, CH on Cp). ¹¹B-NMR:d₈-THF: 41.86 ppm.

Example 8 Preparation of (i-Pr)₂NB(C₅H₄)₂Ti(Cl)NMe₂ (7)

A solution of 15 mmol of (5) in 30 ml of hexane was cooled to −60° C.and a solution of 3.35 g (15 mmol) of Ti(NMe₂)₄ in 10 ml of hexane wasadded dropwise. The solution was slowly warmed to 20° C., with thereaction solution taking on a distinct deep red color above about −15°C. The solution was stirred at 20° C. for 1 hour and reacted with 1.38 g(7.5 mmol) of (C₄H₈N)₂BCl, stirred at 20° C. for another 2 hours,evaporated to about 50% of its volume under reduced pressure andcrystallized by storage at −30° C. After 1 day, the precipitated solidwas filtered off. Yield: 3.02 g (55%) Analysis (C₆D₆): ¹¹B-NMR: 40.3ppm; ¹H-NMR: 1.04 (d, 12H, CHCH₃); 3.10 (s, 6H, N(CH₃)₂; 4.87, 5.43,6.70, 6.90 (each m, each 2H, CH_(Cp)); MS (EI): 366 (M⁺, 15%), 322(M⁺-NMe₂, 100%), 287 (M⁺-NMe₂-Cl, 10%), 176 (TiCp₂, 10%).

Example 9 Preparation of (i-Pr)₂NB(C₅H₄)₂TiCl₂ (8)

The preparation was carried out by a method analogous to the preparationof (7) using 5.9 mmol of (5) in 20 ml of hexane, 6.0 mmol (1.36 g) ofTi(NMe₂)₄ in 5 ml of hexane and 6.1 mmol (1.11 g) of (C₄H₈N)₂BCl.

Yield: 920 mg (43%); ¹¹B-NMR: 40.7; ¹H-NMR: 1.36 (d, 12H, CHCH₃); 5.61,7.06 (each m, each 4H, CH_(Cp)).

Example 10 Preparation of (Me₃Si)₂NB(C₅H₄)₂ZrCl₂ (9)

4.13 g (11 mmol) of solid ZrCl₄*2THF were added at −70° C. to asuspension of 3.7 g (11 mmol) of (1) in 30 ml of diethyl ether andrinsed in with 20 ml of toluene. The reaction mixture was slowly warmedto room temperature on the cooling bath, which resulted in the initiallyslightly yellowish color becoming more intense. The mixture was thenstirred at room temperature for 16 hours. The solution was filtered andthen evaporated to about 50% of its initial volume under reducedpressure. This solution was stored at −30° C. After 24 hours, yellowcrystals were obtained. These were filtered off and the mother liquorwas evaporated further and once again stored at −30° C. This gave yellowcrystals. The combined yield was 3.92 g (86%).

¹H-NMR (C₆D₆): δ=0.11 (s, 18H, SiMe₃), 5.16, 6.62 (pseudo-t, 4H; CpH);¹³C-NMR (C₆D₆): δ=5.0 (s, SiMe₃), 109.6, 124.9 (2s, CpH); ¹¹B-NMR(C₆D₆): δ=47.4 (s); MS: m/e (%): 461 (5, M⁺), 446 (3, M⁺-Me), 91 (80,Zr⁺), 66 (40, Cp⁺).

Example 11 Preparation of [iPr₂NB(C₅H₅)C₆H₅NH](10)

A solution of 5.4 g (30 mmol) of iPr₂NBCl₂ in 10 ml of hexane was addeddropwise at 0° C. to a suspension of 2.64 g (30 mmol) ofcyclopentadienylsodium in 25 ml of hexane. The mixture was allowed tocome to room temperature and was stirred for another 2 hours. Theprecipitated NaCl was filtered off and the filtrate was slowly addeddropwise at 0° C. to a suspension of 3.15 g (32 mmol) of lithium anilidein 20 ml of toluene. The mixture was allowed to warm to room temperatureand was then stirred overnight to complete the reaction. The solvent wasthen removed under reduced pressure and the remaining yellow residue wastaken up in 20 ml of benzene, filtered and the filtrate was freed ofsolvent. The solid obtained in this way was sublimed at 85° C. in a highvacuum. This gave 7.91 g of iPr₂NB(C₅H₅)(C₆H₅NH) in virtuallyquantitative yield.

¹H-NMR(499.658 MHz, CD₂Cl₂): δ=1.23 (br. d, 12H, CHCH₃), 2.86 (m, 2H,C₅H₅), 3.59 (m, 2H, CHCH₃), 5.08 (br. s, 1H, NH), 6.2-7.2(m, 8H, C₅H₅,C₆H₅); ¹¹B-NMR(160.310 MHz, CD₂Cl₂): δ=30,06. ¹³C-NMR(125.639 MHz,CD₂Cl₂): δ=23.96, 45.71, 43.44, 46.58 (br), 133.28 (Cp), 135.50 (Cp),137.74 (Cp), 118.70, 119.64, 128.78, 146.10. MS(EI) [m/e,%]: 268 [M⁺,20], 253 [M⁺-Me, 50], 93 [C₆H₅NH₂ ⁺, 100], 65 [C₅H₅ ⁺, 30]. Correctelemental analysis.

Example 12 Preparation of [iPr₂NB(C₅H₅)C₆H₅N{Ti(NMe₂)₂}](11)

0.83 g (3.09 mmol) of (10) was dissolved in 15 ml of toluene and admixedat −78° C. with 0.69 g (3.09 mmol) of [Ti(NMe₂)₄] in 5 ml of toluene.After stirring at −78° C. for 20 minutes, the reaction mixture wasallowed to warm slowly to room temperature and was stirred for another 2hours at room temperature and another one hour at 40° C. The volatileconstituents were removed under reduced pressure, the orange-red residuewas taken up in 20 ml of hexane and the resulting solution wascrystallized by cooling overnight at −30° C. This gave 0.97 g (78%) ofthe titanium complex (11) as an orange solid.

¹H-NMR(499.658 MHz, CD₂Cl₂): δ=0.90 (br., 6H, CHCH₃), 1.45 (br., 6H,CHCH₃), 2.97 (s, 12H, NMe₂), 3.31 (br., 2H, CHCH₃), 5.94 (m, 2H, C₅H₄),6.44 (m, 2H, C₅H₄), 6.73 (m, 2H, C₆H₅), 6.83 (m, 1H, C₆H₅).¹¹B-NMR(160.310 MHz, CD₂Cl₂): δ=27.76; ¹³C-NMR(125.639 MHz, CD₂Cl₂):δ=21.36 (br), 27.01 (br), 44.62 (br), 46.11 (br), 47.90 (NMe₂) 120.95(Cp), 124.00 (Cp), 115.81, 119.99, 128.16, 155.48. MS (EI) [m/e, %]: 402[M⁺, 45], 387 [M⁺-Me, 5], 358 [M⁺-NMe₂, 65], 314 [M⁺-2 NMe₂, 1001, 93[C₆H₅NH₂ ⁺, 95], 64 [C₅H₄ ⁺, 45]. Correct elemental analysis.

Example 13 Preparation of [iPr₂NB(C₅H₄)C₆H₅N{TiCl₂}](12)

0.50 g (4.60 mmol) of (CH₃)₃SiCl in 2 ml of hexane was added at 0° C. toa solution of 0.17 g (0.42 mmol) of the titanium complex (11) in 10 mlof hexane. The solution was warmed slowly to room temperature andstirred overnight. The yellow solid which precipitated was isolated bydecanting off the supernatant solution and was washed twice with 10 mleach time of hexane. The solid obtained in this way was dried underreduced pressure. This gave 0.16 g of the titanium complex (12) invirtually quantitative yield.

¹H-NMR(499.658 MHz, CD₂Cl₂): δ=0.90 (d, 6H, J³=6.71 Hz, CHCH₃), 1.54 (d,6H, J³=6.71 Hz, CHCH₃), 3.14 (m, 1H, J³=6.71 Hz, CHCH₃), 3.41 (m, 1H,CHCH₃), 6.44 (m, 2H, C₅H₄), 7.08 (m, 2H, C₅H₄), 6.91 (m, 2H, C₆H₅),7.14; (m, 1H, C₆H₅), 7.38 (m, 2H, C₆H₅). ¹¹B-NMR(160.310 MHz, CD₂Cl₂):δ=28.39. ¹³C-NMR(125.639 MHz, CD₂Cl₂): δ=21.40, 27.72, 45.20, 47.28,122.52 (Cp), 124.32, 127.21, 129.62, 152.39. MS(EI) [m/e, %]: 384 [M⁺,15], 369 [M⁺-Me, 30], 348 [M⁺-Cl, 50], 333 [M⁺—C₁-2 Me, 20], 93(C₆H₅NH₂⁺, 70], 64 [C₅H₄, 25]. Correct elemental analysis.

Example 14 Preparation of [iPr₂NB(C₅H₅)tBuNH](13)

A solution of 8.19 g (45 mmol) of iPr₂NBCl₂ in 30 ml of hexane was addeddropwise at 0° C. to a suspension of 3.96 g (45 mmol) ofcyclopentadienylsodium in 50 ml of hexane. The mixture was allowed tocome to room temperature and was stirred for a further 16 hours. Theprecipitated NaCl was filtered off and the filtrate was slowly addeddropwise at 0° C. to a suspension of 3.52 g (45 mmol) of LitBuNH in 20ml of toluene. The reaction mixture was allowed to warm to roomtemperature and was then stirred overnight to complete the reaction. Thesolvent was then removed under reduced pressure and the remaining yellowresidue was taken up in 50 ml of benzene, filtered and the filtrate wasfreed of the solvent. The solid obtained in this way was dried in a highvacuum. This gave 8.83 g of (iPr₂NB(C₅H₅)(tBuNH) (13) (79%).

¹H-NMR(499.658 MHz, C₆D₆): δ=1.08 (br. d, 6H, CHCH₃), 1.12; (br d, 6H,CHCH₃), 1.11 (s, 9H, C(CH₃)₃), 1.18 (S, 9H, C(CH₃)₃), 3.24 (m, 2H,CHCH₃), 3.37 (m, 2H, CHCH₃), 2.86 (m, 2H, CH_(2Cp)), 3.05 (m, 2H,CH_(2Cp),) 6.40-6.76 (m, 6H, C₅H₄). ¹¹B-NMR (160.310 MHz, C₆,D₆):δ=29.82. ¹³C-NMR(125.639 MHz, C₆D₆): δ=23.30, 33.31, 33.74, 33.96,43.12, 46.9, 49.37, 49.64, 131.82, 133.82, 135.39. MS (EI) [m/e, %]: 248[M⁺,10], 233 [M⁺-Me, 45]. Correct elemental analysis.

Example 15 Preparation of [iPr₂NB(C₅H₄)tBuN{Ti(NMe₂)₂}](14)

0.71 g (2.87 mmol) of iPr₂NB(Cp)tBuNH (13) was dissolved in 10 ml oftoluene and admixed at −78° C. with 0.64 g (2.87 mmol) of [Ti(NMe₂)₄]dissolved in 5 ml of toluene. After stirring at −78° C. for 20 minutes,the reaction mixture was allowed to warm slowly to room temperature andwas stirred for another 2 hours at room temperature and another one hourat 40° C. The volatile constituents were removed under reduced pressure,the orange-red residue was taken up in 20 ml of hexane and the solutionobtained in this way was crystallized by cooling overnight at −30° C.This gave 0.90 g (82%) of the titanium complex (14) as an orange solid.

¹H-NMR(499.658) MHz, C₆D₆): δ=1.17 (br d, 12H, CHCH₃), 3.19 (s, 12H,NMe₂), 3.62 (m, 2H, CHCH₃), 5.92(m, 2H, C₅H₄), 6.49 (m, 2H, C₅H₄), 6.73(m, 2H, C₆H₅), 6.83 (m, 1H, C₆H₅), 7.14; (m, 2H, C₆H₅). ¹¹B-NMR(160.310MHz, C₆D₆): δ=29.82. MS(EI)[m/e,%]: 382 [M⁺,5], 339 [M⁺—NMe₂,60], 248[M⁺-Ti-2NMe₂,35], 233 [M⁺-Ti-2NMe₂-Me,100].

Example 16 Preparation of [iPr₂NB(C₅H₄)tBuN{TiCl₂}](15)

0.65 g (6 mmol) of (CH₃)₃SiCl in 2 ml of hexane was added at 0° C. to asolution of 0.45 g (1.18 mmol) of the titanium complex (14) in 10 ml ofhexane. The solution was slowly warmed to room temperature and stirredfor another 4 hours. The yellow solid which precipitated was isolated bydecanting off the supernatant solution and was washed twice with 10 mleach time of hexane. The solid obtained in this way was dried underreduced pressure. This gave 0.38 g of the titanium complex (15) (88%).

¹H-NMR(499.658 MHz, C₆D₆): δ=0.85 (d, 6H, J³=6.71 Hz, CHCH₃), 1.32 (d,6H, J³=6.71 Hz, CHCH₃), 3.04 (m, 1H, CHCH₃), 4.03; (m, 1H, CHCH₃), 6.22(m, 2H, C₅H₄), 6.83 (m, 2H, C₅H₄). ¹¹B-NMR(160.310 MHz, C₆D₆): δ=32.25.MS(EI)[m/e,%]: 365 [M⁺, 5], 350 [M⁺-Me,45], 322 [M⁺-iPr,50].

Example 17

Ethylene polymerization:

General polymerization method:

In a 250 ml autoclave which had been flushed with inert gas, the amountindicated in Table 1 of the metallocene (with the central metal M=Ti orZr) was dissolved in a little toluene. The appropriate amount of MAO(methylaluminoxane, 10% strength by weight in toluene) was then addedthereto (Al:M=100:1). This gave a total volume of about 100 ml. Theautoclave was then pressurized with ethylene to a pressure of 5 bar. Thepolymerization was carried out at 20° C. for 15 minutes. The autoclavewas subsequently vented and the polymer was filtered off. Further dataare given in Table 1.

TABLE 1 Al:M Temp. Polym. time Amount used Yield Activity (g of etavalue Complex (mol:mol) (° C.) (min) (mg/g) (g) PE/g of cat. *h) (dl/g)7 100 20 15 18.6 24.4 5250 3.35 9 1000 20 15 24.4 17.04 3777 n.d. 9 65060 5 10.2 7.74 9106 n.d. 12 1000 60 10 15.2 1.80 711 1.52 15 1000 60 3013.2 0.98 148 0.93 n.d.: not determined

We claim:
 1. A metallocene complex of a metal of subgroup 5 or 6 of thePeriodic Table of the Elements, in which at least one substituted orunsubstituted cyclopentadienyl radical is bonded to an element of groupIII of the Periodic Table of the Elements, which element of group III ofthe Periodic Table of the Elements is a constituent of a bridging memberbetween this cyclopentadienyl radical and the metal atom, and whichelement of group III of the Periodic Table of the Elements carries, asthe only other substituent, an organonitrogen, organophosphorus ororganosulfur group.
 2. A process for the preparation of a metallocenecomplex as of the formula

in which M is a metal atom of subgroup 4, 5 or 6 of the Periodic Tableof Elements, D is an element of group III of the Periodic Table of theElements, R¹ R², R³, R⁴ are hydrogen C₁- to C₁₀-alkyl, 5-7 memberedcycloalkyl, which can for its part be substituted by a C₁-C₁₀-alkylgroup, or are C₆- to C₁₅-aryl or arylalkyl, where two neighboringradicals R¹ to R⁴ can also form 5-7-membered cyclic groups, which fortheir part may be substituted by C₁-C₁₀-alkyl groups or SiR⁶ ₃ groups,or may comprise further fused ring systems, R⁵ is hydrogen,C₁-C₁₀-alkyl, C₆-C₁₅-aryl or -arylalkyl or C₁-C₁₀-trialkylsilyl, R⁶C₁-C₄-alkyl, m is the number of the subgroups of the metal atom M minus2, n is 2 if X¹ is nitrogen or phosphorus, and is 1 if X¹ is sulfur, X¹is nitrogen, phosphorus or sulfur, X² is hydrogen, C₁-C₁₀-hydrocarbyl,N(C₁-C₁₅-hydrocarbyl)₂ or halogen A is a radical

which comprises reacting a compound R⁵ _(n)X¹—BY₂  (II) in which Y ishalogen, with a compound

in which M′ is an alkali metal or alkaline earth metal, in the presenceof a metal alkyl, and then reacting the reaction product with an Mhalide compound and finally with an oxidizing agent.
 3. A metallocenecomplex which is [iPr₂NB(C₅H₅)C₆H₅N{Ti(NMe₂)₂}] or[iPr₂NB(C₅H₄)C₆H₅N{TiCl₂}].
 4. A metallocene complex which isCl₂Ti[(C₅—H₄)₂BN(SiMe₃)₂], (Me₂N)₂Ti[C₅H₄)₂—BN(SiMe₃)₂],(Me₂N)ClTi[(C₅H₄)₂BN(SiMe₃)₂], (i-Pr)₂NB(C₅H₄)₂Ti(Cl)NMe₂ or(Me₃Si)₂NB(C₅H₄)₂ZrCl₂.
 5. A process for the homo- or copolymerizationof C₂-C₁₀-α-olefins which comprises (co)polymerizing theC₂-C₁₀-α-olefins in the presence of the metallocene complex defined inclaim
 1. 6. A metallocene complex of the formula I

in which M is a metal atom of subgroup 4, 5 or 6 of the Periodic Tableof Elements, D is an element of group III of the Periodic Table of theElements, R¹, R², R³, R⁴ are hydrogen, C₁- to C₁₀-alkyl, 5-7-memberedcycloalkyl, which can for its part be substituted by a C₁-C₁₀-alkylgroup, or are C₁- to C₁₅-aryl or arylalkyl, where two neighboringradicals R¹ to R⁴ can also form 5-7-membered cyclic groups, which fortheir part may be substituted by C₁-C₁₀-alkyl groups or SiR⁶ ₃ groups,or may comprise further fused ring systems, R⁵ is hydrogen,C₁-C₁₀-alkyl, C₆-C₁₅-aryl or -arylalkyl or C₁-C₁₀-trialkylsilyl, R⁶ C₁-to C₄-alkyl, m is the number of the subgroups of the metal atom M minus2, n is 2 if X¹ is nitrogen or phosphorus, and is 1 if X¹ is sulfur, X¹is nitrogen, phosphorus or sulfur, X² is hydrogen, C₁-C₁₀-hydrocarbyl,N(C₁-C₁₅-hydrocarbyl)₂ or halogen A is —O—, —S—, —OR⁹, or —SR⁹, whereinR⁹ is hydrogen or alkyl, aryl, silyl, halogenated alkyl or halogenatedaryl comprising up to 10 carbon atoms.
 7. A metallocene complex of ametal of subgroup 4, 5 or 6 of the Periodic Table of the Elements, inwhich at least one substituted or unsubstituted cyclopentadienyl radicalis bonded to an element of group III of the Periodic Table of theElements, which element of group III of the Periodic Table of theElements is a constituent of a bridging member between thiscyclopentadienyl radical and the metal atom, and which element of groupIII of the Perodic Table of the Elements carries, as the only othersubstituent, an organophosphorous, or organosulfur group.
 8. A processfor the homo- or copolymerization of α-olefins which comprises(co)polymerizing C₂-C₁₀-α-olefins in the presence of the metallocenecomplex of claim
 6. 9. A process for the homo- or copolymerization ofα-olefins which comprises (co)polymerizing C₂-C₁₀-α-olefins in thepresence of the metallocene complex of claim 7.